433MHz decode

Using Arduino Networking, Protocols, and Devices
1

Hi all. I'm trying to clone a remote of garage door using arduino with 433MHz transceiver and receiver. All fine, but i can`t get raw code using the rc-switch (just no output), however rfcontrol showed me only this:

400 368 400 368 400 364 3832 756 396 372 776 372 780 368 776
372 780 752 400 368 780 368 780 368 780 368 780 368 780 368 780
740 400 360 776 360 776 364 772 744 396 744 404 732 400 360 776
360 776 740 404 736 400 360 780 360 776 360 776 740 400 360 776
360 780 356 780 360 776 740 400 360 780 740 400 360 780 740 400
360 780 360 780 736 404 356 784 736 404 736 404 736 404 736 408
352 784 356 784 736 404 736 404 356 784 736 404 736 408 352 784
352 788 352 788 748 412 744 412 360 792 360 788 360 792 748 408
744 412 356 792 744 412 744 412 356 792 356 15560

368 400 368 400 368 400 368 400 364 404 364 404 364 400 368 400
368 400 368 400 364 404 368 3832 752 400 368 780 368 784 364 784
368 780 740 400 356 780 360 776 364 772 360 780 360 776 364 772
740 404 356 780 360 776 360 776 740 400 740 400 740 400 360 776
360 780 740 400 736 400 360 780 356 784 356 776 740 408 352 776
360 780 360 776 360 780 736 404 360 780 740 400 356 780 740 404
356 780 360 780 740 400 360 780 740 400 740 404 736 404 736 408
352 784 356 780 740 404 736 408 364 788 748 412 748 408 360 792
360 788 360 792 752 404 752 408 360 792 360 788 364 788 748 408
748 408 360 788 744 412 748 408 360 788 360 15556

368 400 368 400 368 400 368 400 368 400 368 400 368 400 368 408
356 404 368 400 368 396 364 3800 744 396 364 776 364 772 364 772
364 776 744 396 360 776 364 772 368 772 360 776 360 776 364 776
740 400 360 776 364 772 364 776 740 400 740 400 740 400 360 776
360 776 744 396 740 400 360 780 360 776 360 776 740 400 360 776
360 780 360 776 360 780 740 400 360 776 744 400 360 780 736 404
356 784 356 784 736 404 356 780 740 404 736 408 752 404 752 408
364 788 360 788 752 408 752 404 364 788 752 404 752 408 364 784
364 788 364 788 752 408 748 408 360 792 360 788 364 788 752 404
752 404 364 784 748 408 752 404 364 788 364 15552

Is it possible to use that as is for transmit, or some way to decode?

2

Looking at the RFControl library and it has a couple of routines to transmit the received code you show above.
If you connect a transmitter module to a suitable Arduino pin and after a successful capture of the RF code you try transmitting it, does it work? If RFControl cannot capture the code correctly then you need to find another way to do so. If it does work then putting the captured numbers into an array and sending them should be easy.

3

Riva:
If you connect a transmitter module to a suitable Arduino pin and after a successful capture of the RF code you try transmitting it, does it work?

Thank you very much for your response. I have`t tried this, cos I do not know how to do it. Please can you show sketch for example?

4

Perhaps I have found. GitHub - pimatic/homeduino: Arduino library for home control . I`ll try to compile and let you know.

5

Well :slightly_frowning_face: . It became clear to send raw signal required "pulse_sequence" which I can not get by rfcontrol. Any other ideas?

6

What type of garage door is it ?
Many garage door openers use a rolling code receiver, and you cant clone the transmitter remote.

7

TomSam:
Thank you very much for your response. I have`t tried this, cos I do not know how to do it. Please can you show sketch for example?

Once you have read the RF signal an got the number sequence you posted in #1 you then use the procedure (substituting the correct variable names) to send out the signal to a transmitter.
As mauried says this will only work if the transmitter is not using a rolling code.

sendByTimings(int transmitterPin, unsigned int *timings, unsigned int timings_size, unsigned int repeats = 3);
8

mauried:
What type of garage door is it ?

Doorhan.

9

If the remote uses rolling code receiver, is possible to save the transmission from the remote to the receiver (if the garage door did not receive them) and use in the future?

10

is possible to save the transmission from the remote to the receiver (if the garage door did not receive them) and use in the future?

Only in some rather distant future.

Most codes roll over after a large number of transmissions, in the 16 bit case after 65535 button presses on the remote.

The receiver will accept only a message that has been generated within a few button cycles after the last successfully received message.

11

One way to get access to such a system is:

  • receive the original code, but block the garage door reception
  • wait for the user to press the sender again (he will think his transmitter failed)
  • receive it and again block the garage door reception
  • now transmit the old code to the garage doorthen you have one usable code.
12

Id be interested in seeing the blocking technique used to do this.

13
14

Unfortunately, they fail to explain the physics of this little part of the explanation.

The jamming signal prevents the receiver from acknowledging the request, but it can be filtered out using GNU Radio to recover the key.

How is it filtered out?

15

How is it filtered out?

Two approaches are suggested in the linked methods.

  1. If you know the jamming signal, you can subtract it directly from the received sum signal (an arbitrary multiplicative constant would have to be determined). Waves obey the superposition principle, which means that they add and subtract linearly.

  2. The jamming signal is created on a slightly different frequency than the keyfob transmitter. The door lock receiver is cheap, and consequently too wide band to discriminate the two, so fails to decode the signal. However, you can use a narrow band notch filter to remove the jamming signal, leaving only the original keyfob signal.

16

Im open to a demo.

17

Well, this guy claims to have demonstrated it. Judge for yourself!

18

In my case, this decision. With pilight-send -p raw --code="xxx xxxx ..." possible to send raw pulse and its worked. Thanks to all.